The optimal explanation of a system of government characterized by divided sovereignty between a central authority and constituent political units is one where power is constitutionally allocated. This division ensures that neither level of government is entirely subordinate to the other within their designated spheres of authority. A common example is the United States, where national powers are enumerated in the Constitution, while powers not delegated to the federal government are reserved to the states, or to the people.
This structure offers several advantages. It allows for local responsiveness, as states or provinces can tailor policies to reflect the unique needs and preferences of their populations. Simultaneously, it provides for national unity and consistency on matters of common interest, such as defense or interstate commerce. Historically, such arrangements have been adopted to balance the desire for centralized governance with the need to preserve regional autonomy and prevent the concentration of power in a single entity. The design is often a compromise between a unitary system, where the central government holds supreme authority, and a confederation, where constituent units retain ultimate sovereignty.
